It is standard to mount panels such as ceiling tiles, wall paneling, or floor carpeting or tile by means of a mounting strip and a trim strip. The mounting strip has a seat, typically U-shaped, that receives the edge of the panel and this strip is secured solidly to the support surface, typically by nailing, screwing, or gluing. Then the decorative trim strip is mounted over the mounting strip to dress it up and conceal any poor fit of the strip in the corner.
Thus the installer must laboriously install two separate elements. After going completely around the edge of the ceiling, wall, or floor with the mounting strips and securing the panels in place, he or she must then go completely around again, installing the trim strips. This therefore entails two completely independent operations, typically of nailing and can even involve having to drill two separate sets of holes. Furthermore getting the trim strip to fit tightly is often difficult, and it is virtually impossible to remove and reinstall one of the trim strips since such a trim strip cannot be removed without damaging it so if renovations must be done, new trim strips must be supplied.